Astralpool Hurlcon threaded 3/8" M4 Brass Plug with Hex Head. Used for High-Limit Switches. Hi-Limit switch screws into these brass plugs. They can corrode due to water quality, or where a leak has allowed the 24V from the hi-limit switch to cause electrolytic corrosion. Old ones had a 3/4" head. New ones have a larger head. They are interchangeable. 

Shipped Fast from NSW, VIC, QLD. 
Pick-up is available from our office in Vic. 

It is important to replace or repair these when leaking, and should be checked every 6-12months. This can be one of the biggest causes of damage to gas heaters.

Suits: Later MX, HX, Viron, JX, ICI Heaters. Also suits Jacuzzi J-HN250C & J-HN400C heaters. 

Installing:
Use Pink Thread Tape or a chemical-resistant thread sealant for Sealing threads. Care must be taken not to cause radial cracks in the header manifold around the female threaded area. <-- This is usually caused by over-tightening.

71051  71053 

Other High Limit (Hi Limit) Switches:
42-45C° Inlet Hi Limit (Hurlcon, Astralpool, Raypak, Pentair)
52-55C° Outlet Hi Limit (Hurlcon, Astralpool, Raypak, Pentair)
60C° Outlet Hi Limit AGS (Hurlcon, Astralpool, Raypak, Pentair)
70C° Outlet Hi Limit (Hurlcon, Astralpool HX/JX)
100C°
175C° Flue Temp Sensor (Hurlcon, Astralpool)
Hurlcon / Astralpool HiLimit Locator Brass Threaded Plug